docs: def load(overlay, path=""):
      """
       load - Load a DTB Overlay
  
       Inputs:
        overlay - Overlay Key: SPI2, PWM0, CUST
        path    - Full Path to where the custom overlay is stored
  
       Returns:
        0 - Successful Load
        1 - Unsuccessful Load
        2 - Overlay was previously set
      """
      global DEBUG
      global _LOADED
      if DEBUG:
          print("LOAD OVERLAY: {0} @ {1}".format(overlay,path))
      # SEE IF OUR OVERLAY NAME IS IN THE KEYS
      if overlay.upper() in _OVERLAYS.keys():
          cpath = OVERLAYCONFIGPATH + "/" + _FOLDERS[overlay.upper()]
          if DEBUG:
              print("VALID OVERLAY")
              print("CONFIG PATH:  {0}".format(cpath))
          # CHECK TO SEE IF WE HAVE A PATH FOR CUSTOM OVERLAY
          if overlay.upper() == "CUST" and path == "":
              raise ValueError("Path must be specified for Custom Overlay Choice")
          elif overlay.upper() == "CUST" and _LOADED[overlay.upper()]:
              print("Custom Overlay already loaded")
              return 2
          elif overlay.upper() == "CUST" and not os.path.exists(path):
              print("Custom Overlay path does not exist")
              return 1
  
          # DETERMINE IF WE ARE A CHIP PRO AND WE ARE COMMANDED TO LOAD PWM0
          if is_chip_pro() and overlay.upper() == "PWM0":
              print("CHIP Pro supports PWM0 in base DTB, exiting")
              return 1
  
          # SET UP THE OVERLAY PATH FOR OUR USE
          if overlay.upper() != "CUST":
              opath = OVERLAYINSTALLPATH
              opath += "/" + _OVERLAYS[overlay.upper()]
          else:
              opath = path
          if DEBUG:
              print("OVERLAY PATH: {0}".format(opath))
  
          if overlay.upper() == "PWM0" and _LOADED[overlay.upper()]:
              print("PWM0 Overlay already loaded")
              return 2
  
          if overlay.upper() == "SPI2" and _LOADED[overlay.upper()]:
              print("SPI2 Overlay already loaded")
              return 2
  
          # LOAD THE OVERLAY
          errc = _set_overlay_verify(overlay.upper(), opath, cpath)
          if DEBUG:
              print("_SET_OVERLAY_VERIFY ERRC: {0}".format(errc))
          if errc == 0:
              _LOADED[overlay.upper()] = True
  
      else:
          raise ValueError("Invalid Overlay name specified! Choose between: SPI2, PWM0, CUST")